Fig. 52.—Correct Manner.
A, B, C = Screws.

§ 8. The model would require something in the nature of a vertical fin or keel to give the sense of direction. Four propellers, two for "lift" and two for "drift," would undoubtedly be a better arrangement.

CHAPTER XII.

EXPERIMENTAL RECORDS.

A model flying machine being a scientific invention and not a toy, every devotee to the science should make it his or her business to keep, as far as they are able, accurate and scientific records. For by such means as this, and the making known of the same, can a science of model aeroplaning be finally evolved. The following experimental entry forms, left purposely blank to be filled in by the reader, are intended as suggestions only, and can, of course, be varied at the reader's discretion. When you have obtained carefully established data, do not keep them to yourself, send them along to one of the aeronautical journals. Do not think them valueless; if carefully arranged they cannot be that, and may be very valuable.

Experimental Data.
Form I.

ModelWeightArea of
Supporting
Surface		Aspect
Ratio		Average
Length of
Flight in
Feet		Maximum
Flight		Time of Flight
A. average
M. maximum		Kind and
Direction
of Wind		Direction
of
Flight		CamberAngle of
Inclination of
Main Aerofoil
to Line of
Flight
AM
1
2
3
4
5
6
7
8
9
10
11
12